Dormant seeds of many legumes have been long known to store polysaccharide gums in the middle endosperm layer (Schleiden and Vogel. 1839. Nova Acta Acad. Caesar. Leop.-Carol. 19(1):53-96+6 ic; Nadelmann. 1890. Prings. Jarhb. Wissen. Bot.21:609-691+6 ic.;
Kopooshian and Isely, 1966. Iowa Acad. Sci. 73:59-67). These polysaccharide gums, which are primarily galactomannans, are able to produce gels or viscous solutions at low concentrations, which makes them valuable for many purposes. Also, because the gums are localized in the endosperm, extraction can be accomplished easily by several simple chemical and mechanical means. Although used since antiquity, they have become increasingly valuable for food, cosmetics, pharmaceuticals, textiles, paper, and a wide variety of industrial uses starting in the 1940's (Buckeridge et al. 2000. 283-316 in Gupta and Kuar, eds.
Carbohydrate Reserves in Plants—Synthesis and Regulation. Elsevier). The primary current sources of galactomannans are guar (Cyamopsis tetragonoloba), locust (Ceratonia siliqua), and fenugreek (Trigonellafoenum-graecum), all of which are imported and subject to supply and price uncertainties (Dhugga et al. 2004. Science 303:363-366).
Scientists have for decades attempted to find a good domestic plant source of galactomannan gum. Tookey and Jones (1965. Economic Botany 19:165-174) surveyed 300 species in 139 genera in 31 plant families and concluded that: “. . . it is reasonable to expect that an annual legume will be found that can be developed into a domestic crop source of seed gum.” The work resulted in U.S. Pat. No. 3,116,281 for the legume Crotalaria intermedia, but little else.
Buckeridge et al. (2000. op. cit.) also encouraged searching for a suitable legume, as well as using molecular techniques. The U.S. Patent Application 20040143871 by Dhugga (2004) describes an extensive molecular attempt to produce a variety of galactomannan gums in a variety of plants, with soybean and corn as the primary targets for a domestic source, although he does not name any specific target tissue.
Other than molecular work, no attempt has been made to produce gum in soybean, although Whistler and Saarnio (1957. J. Am. Chem. Soc. 79(22):6055-6057) suggested recovering a trivial yield of galactomannan from waste soybean hulls of unspecified cultivars available at the time, despite that they did not know the tissue containing the galactomannan, and were unaware of any genetic based variability in yield. A similar report by Aspinall and Whyte (1964. J. Chem. Soc. 232:5058-5063) also did not lead to gum production. None of these authors measured the endosperm. The reason for the lack of interest, is that soybean has been considered to have virtually no endosperm, and therefore virtually no galactomannan (Chalon. 1875. Societe Sci. Arts Lettres Hainaut. 10:3-66; Nadelmann (1890. op. cit.); Pammel 1899. Trans. Acad. Sci. St. Louis 9(6):91-273+xxxv ic; Kirkbride et al. 2003. Fruits and seeds of genera in the subfamily Faboideae (Fabaceae). USDA ARS Technical Bulletin 1890. v+1-1218; Buckeridge et al. (2000. op. cit.); Dhugga (2004. U.S. patent application 20040143871); Ma et al. 2004. Can. J. Bot. 82:654-662.). Even though hybridization of soybean with other species in the genus Glycine has been practiced for almost a hundred years (Hymowitz and Singh. 1987. 23-48 in Caldwell, B. E., ed. Soybeans: improvement, production, and uses. Second edition. ASA, CSSA, and SSSA, Madison, Wis.), there has been no attempt to create a cultivated soybean by transferring traits for enlarged endosperm from the wild relatives or landraces, because all prior research indicates such breeding attempts would not lead to larger endosperm. As an example of the indications in the prior research in which endosperm was misidentified as non-endosperm tissue, Yaklich et al. (1989. Crop. Sci. 1304-1309) surveyed the wild species and the cultivated soybean, and inferred in a table that the size of this tissue in wild species was smaller than in the cultivated soybean. Any reader, correctly identifying this tissue as endosperm, would thus conclude that any breeding attempts for endosperm involving wild relatives would likely result in a smaller endosperm in the cultivated plant.
This unfulfilled need for a large endosperm in soybean means that such transgenic methods as Dhugga (2004. U.S. patent application 20040143871) have several disadvantages: (a) transgenic methods add complexity; (b) a non-endosperm target tissue for expression must be chosen, and therefore a suitable and likely novel processing system must be developed and implemented for extraction; and (c) for culinary uses especially, many people are opposed to materials developed by transgenic means.
As shown in the above background section, there really is no prior art for the assessment, enlargement, or subsequent use of soybean endosperm, although there may be some aspects of knowledge and previous techniques that may be adaptable in pursuit of such a goal.
Accordingly, several objects and advantages of the invention are:    (a) to create an enlarged endosperm tissue in a cultivated soybean for the production of natural gums;    (b) to maintain an endosperm tissue of suitable size in a plant with other agronomically desirable traits;    (c) to create an enlarged endosperm tissue in a cultivated soybean which can be utilized for the production of modified gums and other materials;    (d) to create an enlarged endosperm tissue in a cultivated soybean from which materials can be extracted easily;    (e) to create an enlarged endosperm tissue in a cultivated soybean which can be used for chemical and physical manipulation for altered agronomic traits; and    (f) to develop a system for galactomannan and other material production and extraction that gives good yield and minimally interferes with normal soybean processing.
Further objects and advantages will become apparent from a consideration of the ensuing description and drawings.